Plastic hood helps make Viper more aerodynamic

DETROIT -- When DaimlerChrysler rolled out its newest Viper at the Detroit auto show last month, all the talk was about horsepower and speed.But it wasn't just muscle that provided an extra 90 hp for the Viper, boosting it to 600. By taking advantage of the sheet-molded plastic compound used for the hood, designers of the 2008 Viper SRT10 were able to create a more aerodynamic flow and better engine performance."We need to stay light and cost-effective," says Herb Helbig, design powertrain engineer for the Chrysler group team that oversees the Viper and other performance cars for the automaker.The new Viper retains the plastic body panels of past sports cars and continues the use of carbon fiber for structural parts, including the front fender supports.But it's the hood, molded by Meridian Automotive Systems Inc., that provides the most dramatic difference. Chrysler designed a 4-inch rise at the center and openings along each side to help circulate the air better within the engine compartment.Composites are showing up on cars and trucks already in production even if they don't make headlines, says Keith Bihary, automotive sales manager for Molded Fiber Glass Cos. and chairman of the Automotive Composites Alliance in Detroit."There is quite a bit of composites used out there, especially when the weight of the vehicle is a concern," he says.Molded Fiber, of Ashtabula, Ohio, molded the composite panels on the first Corvette and is still making composite structural parts on the newest Corvettes, now using carbon fiber.Michigan companies Meridian, of Allen Park, and Continental Structural Plastics, of Troy, are turning out composite boxes for thousands of trucks sold annually by both U.S. and Japanese automakers.General Motors, which is eliminating thermoplastic body panels from its Saturn cars, is using GE Plastics' Noryl GTX resin for fenders on the Hummer."We're continuing to find places in all the market segments," says Gary Landsettle, North American commercial director for Ashland Chemical Co.'s composite polymers business unit, based in Dublin, Ohio.He adds: "They're seeing how composites can translate into lower-volume vehicles, change design and improve weight."You may e-mail Rhoda Miel at rmiel@crain.com

Plastic hood helps make Viper more aerodynamic

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